Carbon nanotubes

A diagram showing different ways to "roll up" carbon nanotubes from planar graphene. The orientation of the hexagonal lattice affects the electrical properties of the tube. Published under the GNU Free Documentation License by Wikipedia user Mstroeck.

The electrical properties of single-wall nanotubes vary from metallic to semiconducting depending on the diameter and chirality of the carbon lattice. Here we see an "armchair" metallic nanotube and a "zigzag" semiconducting nanotube.

Carbon nanotubes are allotropes of carbon in the fullerene family, discovered in 1991 (more or less). Rolling sheets of graphene at different chiral angles creates fullerenes with different electrical properties, making them highly suitable for use in nanoscale electronics, as well as other nanotechnological applications. Nanotubes can be either single-walled or multi-walled, and can be joined together with other fullerenes to form a wide variety of structures. Due to their high tensile strength, diverse electrical and mechanical properties, and versatile carbon chemistry, nanotubes—along with graphene and other fullerenes—represent an important hexagonal contribution to the emerging field of nanotechnology.